Luminescence thermometry is presently used to determine the temperature of an object without having to make physical contact with the object.
A photoluminescent material commonly known as a thermographic phosphor is applied to the object whose temperature is to be measured. The photo luminescent material is stimulated with pulsed UV light. The photoluminescent material emits, in response, a pulse of light generally at a lower frequency (e.g. visible light). This pulse decays exponentially with time. The exponent is related to the temperature of the luminescent material and hence the temperature of the object. The pulses emitted by the photoluminescent material are collected and their decay times are measured and compared against calibrated results to determine the temperature of the object.
Alternatively, a temperature dependence of the wavelength spectrum of the emitted light is used to determine temperature.
An optical fibre is typically used to direct the incident light onto the photoluminescent material. The same fibre is used to collect the light emitted in response by the photoluminescent material. However, the use of the same fibre for emission and collection creates fluorescence which adds noise.
It would be desirable to provide an improved apparatus for luminescence thermometry and for measuring other values via luminescence.